intrigeri, lamby: I'm not feeling comfortable with ikiwiki's perl code base, and wonder how you feel about taking over doing the actual investigation + patching, if it comes to that.

I've already hunted and fixed a few such things in ikiwiki, and know its codebase pretty well due to my serious involvement in it in the past. Count me in!

Great! Then I hand this ticket over to you now; 3 out of 3 "external" reports exhibit this exact issue (and nothing else) so it indeed seems like a legit problem.

With this I mean that all three reports are identical. (Well, modulo things that are expected to change, like tempfile-generated names in "│ │┄ stderr from `unsquashfs -s /space/azazel/tmp/tmpesvak427_diffoscope/0/372`:").